Biometric techniques following fingerprint recognition techniques are proposed in an access control, attendance management, building integrated system, automatic teller machine, computer security field, e-commerce authentication, airport information system, and the like. Among other things, face recognition is a technique to recognize persons using face information having unique characteristics.
A typical face recognition system stores face information or the like of users who are registered in the form of a database and authenticates a user by comparing to pre-stored user information when the user tries to authenticate him/her. An authentication system using the biometric inclusive of the face recognition system shows a higher probability of recognition error as the registered users increase.